Prioritising islands for the eradication of invasive vertebrates

Invasive alien species are one of the primary threats to native biodiversity on islands worldwide. Consequently, eradicating invasive species from islands has become a mainstream conservation practice. Deciding which islands have the highest priority for eradication is of strategic importance to allocate limited resources to achieve maximum conservation benefit. We conducted a prioritization of over 2000 islands ranging from the sub-Antarctic to the tropics in 11 UK overseas territories by carefully considering all threatened native terrestrial vertebrates and all invasive terrestrial vertebrates occurring on these islands. Our approach includes eradication feasibility, distinguishing between the potential and realistic conservation value of an eradication, which reflects the benefit that would accrue following eradication of either all invasive species or only those species for which eradication techniques currently exist. We identified the top 25 priority islands for invasive species eradication which together would benefit extant populations of 135 native species including 38 globally threatened species. This prioritization can be rapidly repeated if new information or techniques become available, and the approach could be replicated elsewhere in the world. The same process is also being used to identify priorities across the 9600 islands in the UK, Isle of Man and the Channel Islands.

Project objectives

Priority list of islands in the UK where invasive vertebrate eradication would yield the highest benefit

Key dates so far

Prioritisation for UK overseas territories is complete

Data collection for UK islands is complete

Prioritisation for UK islands is in progress

Work planned or underway

Prioritisation for UK islands is in progress

Results

We identified the top priority islands for invasive species eradication which together would benefit extant populations of 135 native species including 38 globally threatened species. These islands include world heritage sites including Gough Island (South Atlantic) and Henderson Island (South Pacific) with unique seabird colonies, and Anegada and Little Cayman in the Caribbean, which are home to a unique and diverse reptile fauna.